docs: def get_by_id(self, id):
          """
          Return object based on ``child_id_attribute``.
  
          Parameters
          ----------
          val : str
  
          Returns
          -------
          object
  
          Notes
          -----
          Based on `.get()`_ from `backbone.js`_.
  
          .. _backbone.js: http://backbonejs.org/
          .. _.get(): http://backbonejs.org/#Collection-get
          """
          for child in self.children:
              if child[self.child_id_attribute] == id:
                  return child
              else:
                  continue
  
          return None